The Cancer Epidemiology Program (CEP) brings together 25 investigators from 11 Departments at Stanford and the Northern California Cancer Center (NCCC) in a collaborative approach to reducing the burden, incidence, mortality and morbidity of cancer through innovative and interdisciplinary epidemiologic research. This goal is accomplished through observational research in four areas: cancer surveillance; cancer etiology and risk assessment; early cancer detection; and cancer treatment, prognosis and quality of life. The study of disparities among racial/ethnic/cultural groups forms a theme cross cutting all of these areas. The specific aims of the four targeted research areas are: Cancer surveillance: Describe cancer risk factors and spatial and temporal trends in cancer incidence and mortality; identify scientific hypotheses for further study; conduct methodologic studies to improve data quality; and gather data as new technologies and treatments are introduced into medical practice. Cancer etiology and risk assessment: Convene multidisciplinary expertise to study the complex interactions of molecular, genetic, behavioral and environment factors that affect cancer occurrence. Early detection of cancer: Evaluate the use of new technologies to detect cancers before they have spread and increase understanding of the risks and benefits of screening. Cancer care, prognosis and quality of life: Conduct observational studies of cancer treatments and other cancer care to determine their diffusion, utilization and effect on patient outcomes by characteristics of patients, providers and delivery systems. Identify genetic, molecular and other determinants of recurrence and survival in cancer patients, and factors related to quality of life for cancer patients and families.